European Commission president Jean-Claude Juncker has taken eight long weekends since November

A source said: "After all that money was spent on the brand new office, it turns out he's never there anyway."

The out-of-touch Commission said the £220,000 spent on refurbishing Juncker's office was "necessary".

But Robert Oxley, campaign director of Business for Britain, slammed the "stupendous waste of money".

Mr Juncker has often been described as an absent European Commission president who treats the role as a part-time job.

Some have complained about his tendency to pass his workload onto junior colleagues.

But new, independent analysis shows the chief diplomat – and a host of other senior policymakers – are routinely working two, three or four-day weeks, with the rest of their time spent “working from home”.

Scrutiny of EU commissioners’ diaries revealed senior bureaucrats are regularly arriving back to work on Tuesday after a long weekend, with Mr Juncker enjoying an extended break at least once a month, on average.

The worst offender was the economics commissioner Pierre Moscovici, who has enjoyed 13 long weekends in his native Paris over the 24 weeks since the commission took office on November 1.

The Wall Street Journal’s Brussels’ blog found the Danish Competition Commissioner Margrethe Vestager was next on the list, spending Mondays or Friday away from her desk eight times since taking office.

She was followed by Commission president Mr Juncker, who enjoyed six extended weekends away from Brussels.

The roll-call of Europe’s top diplomats who are likely to be left red-faced by the disclosure includes regional-policy commissioner Corina Cretu, who went back to her home town Bucharest on five occasions — on one occasion as early as Wednesday.

“Sometimes I’m hearing these rumours… ‘The president is not there’, but I’m here all day, even during bank holidays and even on Good Friday.

“I was the only one in the building on Good Friday, which is a Commission holiday… I’m working 12, 14, 16 hours per day.”

He continued: “When I’m delivering a speech, I’m spending hours and hours reading documents because I want to know what is this about and I’m putting questions to cabinet members, to others, to commissioners.

“I do want to know as much about as many things that I can know.”

However, the fact that Mr Juncker is yet to move permanently to Brussels will fuel speculation that he is still a “part-time” president.

Commissioners are entitled to travel abroad and to claim expenses for those meetings, plus a daily allowance of €50 to €100.

The payouts are on top of their monthly salary of over €20,000 (£14,000), with Mr Juncker earning a basic yearly salary of €304,212 (£218,000), plus a range of generous benefits.